It wasn't to track people. It was to ensure authenticity. Thus, you could always go to an Intel website, type in your CPU's ID, and be told if it is a genuine Intel CPU at the advertised clockspeed or a fake, possibly running overclocked. There is no way that ID could have been used to track anyone any more than your MAC address can. There must exist software to grab the ID and a server on the internet to collect this data. Such activity would be very, very obvious and was never planned.